Ambient space

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table of contents Katrin's work in progress here

This section will combine the techniques of [HWZ-GW] and [Li-thesis] to construct topological ambient spaces {\mathcal  {X}}(\underline {x}) of the moduli spaces of pseudoholomorphic polygons \overline {\mathcal  {M}}(\underline {x})=\overline \partial _{{J,Y}}^{{-1}}(0), within which polyfold theory will construct the regularized moduli spaces \overline {\mathcal  {M}}(\underline {x};\nu ). These will arise naturally from the data that was fixed when constructing the (unperturbed) moduli spaces of pseudoholomorphic polygons as part of the polyfold constructions for Fukaya categories:

We are given Lagrangians L_{i}\subset M indexed cyclically by i\in \mathbb{Z } _{{d+1}} and a tuple of generators \underline {x}=(x_{0},\ldots ,x_{d})\in {\text{Crit}}(L_{0},L_{d})\times \ldots \times {\text{Crit}}(L_{{d-1}},L_{d}) in their morphism spaces. These sets of generators depend on the choices of Morse functions f_{i}:L_{i}\to \mathbb{R} on each Lagrangian and of Hamiltonian vector fields X_{{L_{{i-1}},L_{i}}} whose time-1-flow produces transverse intersections \phi _{{L_{{i-1}},L_{i}}}(L_{{i-1}})\pitchfork L_{i} whenever L_{{i-1}}\neq L_{i}. We moreover fix metrics on each L_{i} so that the gradient vector fields \nabla f_{i} are Morse-Bott and have standard Euclidean form near the critical points, such that the compactified Morse trajectory spaces \overline {\mathcal  {M}}(x_{i},L_{i}) inherit a natural smooth structure (see [1]). On the other hand, the construction of the ambient space {\mathcal  {X}}(\underline {x}) will be independent of the choice of almost complex structure on the symplectic manifold M. The only auxiliary choice that we need to make is a (sufficiently small - as will be discussed elsewhere) Sobolev decay constant \delta >0. Then - as set - we define the ambient space as

{\mathcal  {X}}(x_{0};x_{1},\ldots ,x_{d}):={\bigl \{}(T,\underline {\gamma },\underline {z},\underline {w},\underline {{\hat  \beta }},\underline {u})\,{\big |}\,{\text{1. - 8.}}{\bigr \}}/\sim

where the data is the same as in the construction of the moduli spaces of pseudoholomorphic polygons \overline {\mathcal  {M}}(\underline {x}), except for maps not necessarily being pseudoholomorphic but just of Sobolev H^{{3,\delta }}-regularity. We indicate these differences in boldface.

1. T is an ordered tree with sets of vertices V=V^{m}\cup V^{c} and edges E,

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equipped with orientations towards the root, orderings of incoming edges, and a partition into main and critical (leaf and root) vertices as follows:

2. The tree structure induces tuples of Lagrangians \underline {L}=(\underline {L}^{v})_{{v\in V^{m}}}

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that label the boundary components of domains in overall counter-clockwise order L_{0},\ldots ,L_{d} as follows:

3. \underline {\gamma }=(\underline {\gamma }_{e})_{{e\in E}} is a tuple of generalized Morse trajectories

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in the following compactified Morse trajectory spaces:

4. \underline {z}=(\underline {z}_{v})_{{v\in V^{m}}} is a tuple of boundary points

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that correspond to the edges of T, are ordered counter-clockwise, and associate complex domains \Sigma ^{v}:=D\setminus \underline {z}_{v} to the vertices as follows:

5. \underline {w}=(\underline {w}_{v})_{{v\in V^{m}}} is a tuple of sphere bubble tree attaching points for each main vertex v\in V^{m}, given by an unordered subset \underline {w}_{v}\subset \Sigma ^{v}\setminus \partial \Sigma ^{v} of the interior of the domain.

6. \underline {{\hat  \beta }}=({\hat  \beta }_{w})_{{w\in \underline {w}}}\subset \overline {\mathcal  {M}}_{{0,1}}(J) is a tuple of not not-necessarily-pseudoholomorphic trees of sphere maps {\hat  \beta }_{w}=(T^{w},\underline {z}^{w},\underline {u}^{w}).

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These are indexed by the disjoint union \underline {w}=\textstyle \bigsqcup _{{v\in V^{m}}}\underline {w}_{v} of sphere bubble tree attaching points, and consist of the following:

7. \underline {u}=(\underline {u}_{v})_{{v\in V^{m}}} is a tuple of not-necessarily-pseudoholomorphic disk maps for each main vertex.

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That is each v\in V^{m} is labeled by a continuous map u_{v}:\Sigma ^{v}\to M satisfying {\mathbf  {H^{{{\mathbf  3},{\boldsymbol  {\delta }}}}}}-Sobolev regularity, Lagrangian boundary conditions, and matching conditions as follows:

8. The generalized pseudoholomorphic polygon is stable in the following sense:

TODO: update to Ham pert, sphere bubble tree

  • Any main vertex v\in V^{m} whose map has zero energy \textstyle \int u_{v}^{*}\omega =0 has enough special points to have trivial isotropy, that is the number of boundary marked points |v|=\#\underline {z}_{v} plus twice the number of interior marked points \#\underline {w}_{v} is at least 3.
  • Each sphere bubble tree is stable in the sense that

any vertex v\in V whose map has zero energy \textstyle \int u_{v}^{*}\omega =0 (which is equivalent to u_{v} being constant) has valence |v|\geq 3. Here the marked point z_{0} counts as one towards the valence |v_{0}| of the root vertex; in other words the root vertex can be constant with just two adjacent edges.


Finally, two generalized pseudoholomorphic polygons are equivalent (T,\underline {\gamma },\underline {z},\underline {w},\underline {\beta },\underline {u})\sim (T',\underline {\gamma }',\underline {z}',\underline {w}',\underline {\beta }',\underline {u}') if there is a tree isomorphism \zeta :T\to T' and a tuple of disk biholomorphisms (\psi _{v}:D\to D)_{{v\in V^{m}}} which preserve the tree, Morse trajectories, marked points, and maps in the sense that

TODO: add sphere tree iso: Finally, two sphere bubble trees are equivalent (T,\underline {z},\underline {u})\sim (T',\underline {z}',\underline {u}') if there is a tree isomorphism \zeta :T\to T' and a tuple of sphere biholomorphisms (\psi _{v}:S^{2}\to S^{2})_{{v\in V}} which preserve the tree, marked points, and pseudoholomorphic curves in the sense that

  • \zeta preserves the tree structure, in particular maps the root v_{0} to the root v_{0}';
  • \psi _{{v_{0}}}(0)=0 and \psi _{v}(z_{e}^{v})={z'}_{{\zeta (e)}}^{{\zeta (v)}} for every v\in V and adjacent edge e\in E_{v};
  • the pseudoholomorphic spheres are related by reparametrization, u_{v}=u'_{{\zeta (v)}}\circ \psi _{v} for every v\in V.


  • \zeta preserves the tree structure and order of edges;
  • \underline {\gamma }_{e}=\underline {\gamma }'_{{\zeta (e)}} for every e\in E;
  • \psi _{v}(z_{e}^{v})={z'}_{{\zeta (e)}}^{{\zeta (v)}} for every v\in V^{m} and adjacent edge e\in E_{v};
  • \psi _{v}(\underline {w}_{v})=\underline {w}'_{{\zeta (v)}} for every v\in V^{m};
  • \beta _{w}=\beta '_{{\psi _{v}(w)}} for every v\in V^{m} and w\in \underline {w}_{v};
  • the maps are related by reparametrization, u_{v}=u'_{{\zeta (v)}}\circ \psi _{v} for every v\in V^{m}.




The symplectic area function

If no Hamiltonian perturbations are involved in the construction of a moduli space of generalized pseudoholomorphic polygons - i.e. if for each pair \{i,j\}\subset \{0,\ldots ,d\} the Lagrangians are either identical L_{i}=L_{j} or transverse L_{i}\pitchfork L_{j} - then the symplectic area function on the moduli space is defined by

\omega :\overline {\mathcal  {M}}(x_{0};x_{1},\ldots ,x_{d})\to \mathbb{R} ,\quad b={\bigl [}T,\underline {\gamma },\underline {z},\underline {w},\underline {\beta },\underline {u}{\bigr ]}\mapsto \omega (b):=\sum _{{v\in V^{m}}}\textstyle \int _{{\Sigma _{v}}}u_{v}^{*}\omega \;+\;\sum _{{\beta _{w}\in \underline {\beta }}}\omega (\beta _{w})=\langle [\omega ],[b]\rangle ,

which - since \omega |_{{L_{i}}}\equiv 0 only depends on the total homology class of the generalized polygon

[b]:=\sum _{{v\in V}}(\overline {u}_{v})_{*}[D]+\sum _{{\beta _{w}\in \underline {\beta }}}[\beta _{w}]\;\in \;H_{2}(M;L_{0}\cup L_{1}\ldots \cup L_{d}).

Here \overline {u}_{v}:D\to M is defined by unique continuous continuation to the punctures z_{e}^{v} at which L_{{e-1}}^{v}=L_{e}^{v} or L_{{e-1}}^{v}\pitchfork L_{e}^{v}.

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Differential Geometric TODO:

In the presence of Hamiltonian perturbations, the definition of the symplectic area function needs to be adjusted to match with the symplectic action functional on the Floer complexes and satisfy some properties (which also need to be proven in the unperturbed case):